- Quarry Line Derailment
- SR EMU Fleet Survey
- BR EMU Fleet Survey
- Class 33 Farewell Railtour
- Fifty Years of Brighton Electrics
- Kent Coast Electrification
- Last Train From Addiscombe
- Last Train To Dover Western Dock
- Significant Accidents '37-'65
- Southern Electric History and Infrastructure
- Southern Railway semi-fast units
- Southern Region De-icing Trains
- The Growth of the Southern Electric Network
- Waterloo-Exeter Diesel Operations
- Westinghouse Automatic Air Brake
Southern Region De-icing Trains
This article was written by Gregory Beecroft and appeared in the February 1982 edition of Live Rail sent bi-monthly to members under the title "This Is The Ice Age of the Train". Since 1982 there have been numerous changes to the de-icing train fleet which is now operated by Network Rail. The fundamental problem of ice and snow on the traction current third rail remains.
Winter weather is one of the most intractable operating problems on the Southern Region. When there is a heavy snowfall or severe icing services can be very badly disrupted, or even totally suspended. However, as such conditions rarely occur on more than two days in an average year it is difficult to justify major expenditure on snow clearance and other measures. It is often asked why it is that snow causes the Southern to grind to a halt whereas the Swedish Railways, for example, can keep going in far worse conditions. The answer is that in Sweden severe weather can be guaranteed for most of the winter and so greater expenditure is worthwhile. The Southern is faced with the task of overcoming severe weather as it arises with the minimum possible amount of equipment.
It is easier to deal with problems if they can be anticipated, and during the winter months the Southern receives special weather forecasts several times each day from the London Weather Centre. Weather information is also obtained from rail staff. Signalmen at various locations telephone a weather report to the divisional control office at 04:00 daily, including information on the state of the track - whether it is wet, frosty or covered with snow, for example. Signalmen are also obliged to inform control In the event of it becoming foggy. Certain station managers inform control if weather conditions are changing so that problems are likely to occur. Thus a comprehensive picture of the weather throughout the region is maintained.
Weather problems arise from two main causes; low temperatures and precipitation. If the weather is dry, low temperatures do not cause too many problems. The water cooling systems of Class 33 and 47 diesel locomotives are not treated with antifreeze so the engine has to be run for one hour in every four in order to prevent freezing. Class 08, 09 and 73 locomotives do have anti-freeze in the cooling water, but during cold weather the shunting locomotives engines have to be run for one hour in every eight so as to conserve battery condition. Diesel-electric multiple-units are also treated with anti-freeze and special precautions are not normally required.
During very cold weather it may become necessary to drain water from the tanks on passenger stock. The plumbing of 1953 and later stock, and also rebuilt 4Cep, is better insulated than that on earlier units and only needs to be drained under very severe conditions; if the temperature is likely to fall to -40C or below and remain significantly below freezing for 24 hours or more. In the event of a large number of units having to be drained, priority is given to 2Hap, unrebuilt 4Cep and 4Bep, and to diesel units. Berthed units which require draining have to be fully heated and lit if there is likely to be an appreciable delay in having the work carried out. Drained units cannot be used in service unless the water heater is isolated, and water cans have to be provided in the lavatories. Carriage washing machines cannot be used during very cold weather due to the risk of ice forming on carriage stepboards, and frozen flails breaking carriage windows and damaging paintwork. The machines themselves are protected against froSt Moisture in train air brake pipes can freeze, causing brakes to fail.
It is comparatively rare for the weather to be both dry and very cold, and most problems result from freezing rain, ice and snow. Snow can completely block lines, and also has to be cleared from platforms, footpaths and station forecourts. Twenty six Class 33 locomotives are fitted with miniature snow ploughs, which are effective for clearing snow up to 1ft 6in deep. For snow drifts and greater depths of snow it is necessary to resort to locomotive-propelled snowploughs, eight of which are allocated to the Southern Region. These are converted from steam locomotive tenders. Snowploughing is not as straightforward as it might appears. If a snowplough is propelled too fast or if attempts are made to clear a greater depth of snow than the plough is designed to deal with, there is a risk of the snowplough and locomotive being derailed, and they will almost certainly become stuck. After a snowplough has operated it is necessary for the snow which has been thrown clear of the rails to be shovelled off the conductor rail, points machines and other lineside equipment.
Points can easily become jammed by snow, but over 2,500 sets of points on the Southern are equipped with heaters to prevent this happening. Heaters are fuelled by propane, town gas or electricity. Some electric point heaters are thermostatically controlled and those which are not are remotely controlled. However, gas heaters have to be lit and switched off manually on site. This is normally done by permanent way staff.
The biggest problem is that of power supply, particularly the formation of ice and snow on the conductor rail. Difficulties are most likely to arise if snow or heavy rain is followed by freezing rain, or if snow remains on the conductor rail under a clear sky. In the former case ice forms on the rail, and in the latter the snow becomes bonded to the rail. The most obvious result is loss of contact between the conductor rail and train pick up shoes, but a converse difficulty is the pick up shoes of berthed units becoming frozen to the rail. Frosty weather also causes increased arcing between conductor rails and pick up shoes, due to ice crystals in the air acting as a conductor, and this results in severe wear to the pick up shoes.
Modern pick up shoes are designed so as to throw small obstructions, snow and ice off the conductor rail, but can only cope with limited quantities. Until the mid 1940's snow was cleared from conductor rails by means of special brushes attached to certain steam locomotives, and the Bulleid electric locomotives were fitted with conductor rail scrapers. Brushes were exchanged between steam locomotives quite frequently. In 1945 six de-icing trailers were converted from ex-LBSCR coaches from two-coach trailer sets, with a further four following in 1946. The trailers spread a de-icing fluid on the rails, and operated marshalled between two Sub or similar units, or could be steam hauled. They were based at Brighton, Selhurst, Wimbledon Park, Fratton and Gillingham. Old and new coach numbers were:
In 1957 the first two-coach de-icing units were introduced. These were formed of converted Sub motor coaches, which were converted LBSCR ac vehicles. The units were both based at Fratton, and numbers were:
Unit S90 DS347 (ex-8741) DS348 (ex-8899) from unit 4557
New de-icing stock, with improved equipment, entered service in 1959/60 and replaced all of the earlier stock. This comprised ten two-coach units and four de-icing trailers. The former were converted from short-underframe 3Sub motor coaches dating from 1925 and the latter were all-steel Sub augmentation trailers of 1946. The trailers were equipped to operate in multiple with EPB type stock, but the two coach units retained their original traction and control equipment. All vehicles were fitted with fluid tanks and spreader shoes. The trailers were based at Ramsgate and the two-coach units at the same depots as the earlier stock. The de-icing trailers were numbered
DS70050 ex-10392 from unit 4345
The formations of the two coach units were:
S92 DS70044 (ex-8456) DS70045 (ex-8455) from unit 4345
DS70044 was damaged in 1961 and replaced in the following year by DS70173 (ex-8457 from unit 4346). The units were renumbered in sequence 011-020 in 1968/69, and all vehicle numbers were subsequently prefixed A. All of the two-coach units were withdrawn by the end of 1979, and trailer ADS70087 was withdrawn in 1981 with the other three trailers remaining in service.
Three new units were provided for the Bournemouth line in 1967/68. These were converted from 2Hal and 4Lav motor coaches, and differed significantly from the earlier units in that all de-icing equipment was mounted on one coach only. The old traction motors were replaced by the standard EE507 type and the units were adapted to work in multiple with EPB type stock. In the earlier units an operator observed the position of the conductor rail through a ducket in the bodyside, and controlled the flow of fluid accordingly. On the Bournemouth units the flow of liquid was automatically cut off when the spreader shoe ran off a conductor rail. The units were numbered thus:
001 DS70268 (ex-10726 of unit 2608) DS70273 (ex-10500) of unit 2955
The de-icing equipment was mounted on DS70268-70. Unit 001 operated from 1967 until 1969 with 2EPB motor coach 65364 (ex-5750) in place of DS70273. In addition to these three units, de-icing trailer DS 70086 was allocated for use on the Bournemouth line. Vehicle numbers are now prefixed A. Unit 002 was withdrawn following a derailment in 1977. An image of 002 at work in 1970 on de-icing duties may be found in the Gallery pages.
No de-icing unit was provided for the Isle of Wight line, but de-icing equipment was installed in the otherwise unused driving cab of trailer 3 of 4Vec 043. The apparatus was devised, constructed and installed at Ryde depot. It is not possible for the de-icing operator to view the conductor rails, but lamps indicate to which side the rail is located.
Units to replace 011-020 were introduced from 1979 and the last of these should have entered service recently. The units are converted from 4Sub motor coaches, and have traction, control and de-icing equipment similar to that on 001-003. In previous units the de-icing tank has been electrically live when fluid was being spread, as the fluid conducts electricity, but the new units have tanks which are fully insulated by means of a plastic lining. The new units also have additional rail scrapers. Unit formations are thus, de-icing equipment being mounted on the even numbered vehicles:
002 ADB975594 (ex-12658 of 4604) ADB975595 (ex-10994 of 4127)
The vehicles in units 011-013 may be renumbered the opposite way round from as shown. It was originally proposed to convert 013 from vehicles 10841/42 from Sub 4384. An additional unit was ordered to replace the original unit 002, resulting in the coach numbers of units 002 and 013 being out of sequence.
De-icing trains operate to fixed diagrams and between them cover most running lines in a single night. The de-icing fluid is not stored at all depots, and certain units have to work during the day to an alternative depot for their tanks to be refilled.
The de-icing fluid itself has been, and still is, the subject of development. The present fluid is an oil which has been formulated to coat the conductor rail and prevent ice and snow from adhering to it. The scrapers on the de-icing units, and the pick up shoes on other trains, can then easily knock ice off the rail. It has not proved practicable to produce a liquid which will prevent ice from forming at all, and which will remain effective for an appreciable period. The requirements that de-icing fluid should not be flammable or corrosive, and should not impede contact between pick up shoes and the conductor rail, limits the range of oils and solutions which can be considered for use. Salt cannot be used to melt ice as this would not only cause severe corrosion of the conductor rail and pick up shoes, but also severe arcing and possible short circuits to earth.
The present designs of shoegear on the Southern do not allow the conductor rails to be boarded over so as to protect them from snow and ice, and also to make the lines safer. It might be possible to modify the shoegear of 1963 and later stock to permit use of a protected third rail, as the main support for the pick up shoe is not the shoe beam attached to the axle boxes but a beam parallel to the axles. However, earlier stock is likely to be in service for another twenty years. Heating the conductor rail is quite impracticable due to the enormous cost, both of equipment involved and fuel.
It is interesting to note that the Southern has never adopted London Transport a practice of fitting passenger units with de-icing equipment. However, the London Transport outdoor network is relatively limited in extent and trains do not switch from one line to another, so it is fairly easily to monitor the de-icing trains and arrange for them to cover all lines. This would be much harder on the Southern, and for the system to the workable a large number of units would need to be equipped for de-icing duties.
Possibly the most promising area for improvement in operations during severe weather is in the field of communications. Radio communication between train crews, station staff and control would make it much easier to report operating difficulties and to arrange prompt assistance for trains which have been disabled by snow and ice. The equipment would be of use in many other circumstances, so much greater expenditure could be justified than would be the case for means to combat severe weather alone.
Now is the winter of our discontent made glorious summer ...... on the ultra high frequency waveband?